Most people I talk to think that logging a mature forest
has to start with clear-cutting.
As a result, my friends feel that the few remaining
areas of old growth in the US and Canada are to be held sacrosanct.
When I point out that old growth is carbon-neutral,
they are first puzzled and then, when the implications have
sunk in, they are angry.
They are puzzled because "carbon-neutral"
is redolent of PR-speak by multinational corporations.

"Carbon-neutral" has gotten a bad name because companies
like
Dell, Google, HSBC, ING Group, PepsiCo, Sky, Tesco,
Toronto-Dominion Bank, Asos, and Bank of Montreal
have at various times declared themselves carbon-neutral.
Carbon-neutrality is a concept that arose in connection
with the Kyoto protocol and means that the organization
concerned offsets their CO2 emissions by activities
that absorb carbon from the atmosphere or by buying such activities
from other organizations that, as one may hope, have
the required net negative carbon emissions
and have not also sold it someone else.
"Carbon-neutral" is a term that reeks of PR shenanigans
and it's mean of me to tar the sacred cause of
preserving Old Growth with that brush.

Yet, although the term is rarely used in this context,
it is a fact that a tract of old growth is carbon-neutral.
The very definition of old growth is that this forest
has reached its maximum biomass.
Sure, its magnificent canopy absorbs CO2 from
the atmosphere, lots of it.
But, by definition, its biomass does not increase.
Therefore, it produces the same amount of CO2
as it aborbs by photosynthesis.
This may seem surprising,
but it becomes obvious when you realize that the
great mass of decaying trunks and the thick layer of humus is
not increasing in mass (total biomass remains constant, remember?)
which means that the carbon in the humus and dead trunks is turned
into CO2 at the same rate as its capture by
photosynthesis.

If you are looking for opportunities to diminish the
decrease the disastrously high carbon dioxide content of the
atmosphere (400 parts per million, more than it has been
in the past half million years),
then don't look to old growth.

Clear-cutting old growth is of course not an answer either.
It messes up the streams, causes erosion,
leaves us with an eyesore for decades,
and it continues the carbon-dioxide production
while it has eliminated the carbon-dioxide absorption of
the canopy.

In spite of what commercial corporations seem to think,
there are other methods of logging than clear-cutting.
An alternative was developed in Germany under the name
"Dauerwald" in the first half of the last century.
Currently it is known as
CCF,
"continuous cover forestry".
The term covers a variety of management systems that have in common
that the trees have a variety of ages with the oldest trees
between a hundred and two hundred years old.

The age distribution should be such that it can be maintained
over the centuries.
Without human intervention biomass would increase
so that the forest as a whole captures more carbon than
it produces.
Logging prevents increase of biomass.
By selective logging one can aim
at an age distribution that maximizes carbon capture.
The carbon captured from the atmosphere is removed in the
form of timber.
One way of slowing the return of this carbon to the atmosphere
is to replace as much as possible concrete in
construction by lumber.
This has the added advantage that making cement releases
large amounts of CO2.

But what about diversity, both in plant and in animal life?
An old growth forest with all its decaying trunks, standing
and fallen, accommodates a great variety
of animal life.
A rigorous application of the CCF idea would result in the
elimination of this.
Thus the true art of forestry is to leave just enough dead
trees so as to support a high degree of diversity in animal
and plant life.